A Coating for Life

Stents that keep weakened and flabby arteries from collapsing have been true life-savers. But once the arteries are strengthened, they become unnecessary. Previously, doctors had no choice but to leave them in place.

"Our new composite fibres consist of a strong core coated with a drug-releasing, or 'eluting,' solution. They combine strength with the desired elements necessary for drug delivery, so they can be used as the basis of biodegradable drug-eluting stents," says Meital Zilberman of Tel Aviv University's Department of Biomedical Engineering.

Her unique coating technology, she adds, can be used to coat both metal stents, which are currently available, and the biodegradable stents now in development. "The main problem with drugs used on stents is that coating manufacturers have been unable to develop a method for releasing them in a controlled manner," explains Zilberman. Insoluble in water, these drugs do not release well from a coating, she explains. A coating made from an extremely porous structure like hers, however, provides a large surface area for diffusion.

Pre-programmed to release the drugs in a controlled manner, the patent-pending fibres can also be designed to dissolve within a precise number of months, so the stent can do its work, then disappear, according to the researcher. Zilberman says that her biodegradable drug-eluting fibres —five times the thickness of a human hair — can be applied in cancer treatments as well, particularly for cancers in hard to reach and sensitive areas such as in the brain, or in small children, she notes.

"When you take a tumour out of the brain, you can't 'clean' the surrounding brain tissue — attempts to do so may lead to additional tissue damage. But if you left our biodegradable drug-loaded fibre in the brain, it could do the work, then disappear when it is no longer needed," she says. And since the fibres are thin and delicate, Zilberman adds, laparoscopic methods can be used for their insertion, further increasing the chances for a full recovery.